Atomic Layer Deposition Deposited Al-Doped ZnO Films for Transistor Application

In this work, we fabricate thin film transistors (TFTs) with an atomic layer deposition (ALD) deposited Al-doped ZnO (AZO) active layer, and study the effects of Al concentration (0, 2.67,3.33,4.00 at. %) on the device performance. The devices with a 2.67 at. % Al concentration show superior electrical properties and stability. The major parameters include a field-effect mobility of 4.99 cm
²
V
^-1
s
^-1
, a sub-threshold swing of 134.15 mV/decade, and an on/off state current ratio over 10
⁶
. Threshold voltage shift under negative and positive bias stress are -0.07 and 0.25 V, respectively.